e1000e: Fix EIAC register implementation

This patch fixes 2 issues:

1. Bits set in EIAC register should be cleared
   from IMS when EIAM is not used.
2. Only bit that corresonds to the interrupt being
   raised should be cleared.

See spec. 10.2.4.7 Interrupt Auto Clear
Signed-off-by: NDmitry Fleytman <dmitry@daynix.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>

hw/net/e1000e_core.c

@@ -2015,13 +2015,17 @@ e1000e_msix_notify_one(E1000ECore *core, uint32_t cause, uint32_t int_cfg)
 
     trace_e1000e_irq_icr_clear_eiac(core->mac[ICR], core->mac[EIAC]);
 
-    if (core->mac[EIAC] & E1000_ICR_OTHER) {
-        effective_eiac = (core->mac[EIAC] & E1000_EIAC_MASK) |
-                         E1000_ICR_OTHER_CAUSES;
-    } else {
-        effective_eiac = core->mac[EIAC] & E1000_EIAC_MASK;
+    effective_eiac = core->mac[EIAC] & cause;
+
+    if (effective_eiac == E1000_ICR_OTHER) {
+        effective_eiac |= E1000_ICR_OTHER_CAUSES;
     }
+
     core->mac[ICR] &= ~effective_eiac;
+
+    if (!(core->mac[CTRL_EXT] & E1000_CTRL_EXT_IAME)) {
+        core->mac[IMS] &= ~effective_eiac;
+    }
 }
 
 static void